Lighting device

ABSTRACT

A lighting device includes a first lighting unit and a second lighting unit. The first lighting unit emits a first light spectrum having a main peak between 525 nm and 585 nm and a first sub peak between 400 nm and 470 nm. The second lighting unit emits a second light spectrum having a main peak between 595 nm and 775 nm and a second sub peak between 400 nm and 470 nm. An intensity of the first sub peak is different from an intensity of the second sub peak.

BACKGROUND OF THE DISCLOSURE 1. Field of the Disclosure

The present disclosure relates to a lighting device, and moreparticularly to a lighting device including the light convertingelement.

2. Description of the Prior Art

In the conventional lighting devices, the green light and the red lightare usually used for color mixing to produce the light having a color(e.g. yellow light). However, the color of the light (e.g. yellow light)may be bluish in the photopic vision condition of the conventionallighting devices for the observer. Therefore, the present disclosureproposes a lighting device that can reduce the above problems.

SUMMARY OF THE DISCLOSURE

In some embodiments, a lighting device includes a lighting unit emittinga light spectrum having a main peak between 520 nm and 780 nm and a subpeak between 400 nm and 470 nm. A second sub peak integral of the lightspectrum is greater than a first sub peak integral of the lightspectrum.

In some embodiments, a lighting device includes a first lighting unitand a second lighting unit. The first lighting unit emits a first lightspectrum having a main peak between 525 nm and 585 nm and a first subpeak between 400 nm and 470 nm. The second lighting unit emits a secondlight spectrum having a main peak between 595 nm and 775 nm and a secondsub peak between 400 nm and 470 nm. An intensity of the first sub peakis different from an intensity of the second sub peak.

These and other objectives of the present disclosure will no doubtbecome obvious to those of ordinary skill in the art after reading thefollowing detailed description of the embodiment that is illustrated inthe various figures and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram illustrating a cross-sectional view of alighting device according to a first embodiment of the presentdisclosure.

FIG. 2 is a schematic diagram illustrating the light spectrum of theoutput light emitted by the first lighting unit or the second lightingunit according to the first embodiment.

FIG. 3 is a schematic diagram illustrating the light spectrums of theoutput lights emitted by the first lighting unit and the second lightingunit according to the first embodiment.

FIG. 4 is a CIE 1931 chromaticity diagram.

FIG. 5 is a schematic diagram illustrating the enlargement of the regionG in FIG. 4 with points of different output lights of the first lightingunits.

FIG. 6 is a schematic diagram illustrating the enlargement of the regionR in FIG. 4 with points of different output lights of the secondlighting units.

FIG. 7 is a schematic diagram illustrating a cross-sectional view of alighting device according to a second embodiment.

FIG. 8 is a schematic diagram illustrating a cross-sectional view of alighting device according to a third embodiment.

DETAILED DESCRIPTION

The present disclosure may be understood by reference to the followingdetailed description, taken in conjunction with the drawings asdescribed below. For purposes of illustrative clarity understood,various drawings of this disclosure show a portion of the electronicdevice, and certain elements in various drawings may not be drawn toscale. In addition, the number and dimension of each device shown indrawings are only illustrative and are not intended to limit the scopeof the present disclosure.

Certain terms are used throughout the description and following claimsto refer to particular components. As one skilled in the art willunderstand, electronic equipment manufacturers may refer to a componentby different names. This document does not intend to distinguish betweencomponents that differ in name but not function. In the followingdescription and in the claims, the terms “include”, “comprise” and“have” are used in an open-ended fashion, and thus should be interpretedto mean “include, but not limited to”.

When an element or layer is referred to as being “on” or “connected to”another element or layer, it can be directly on or directly connected tothe other element or layer, or intervening elements or layers may bepresented. In contrast, when an element is referred to as being“directly on” or “directly connected to” another element or layer, thereare no intervening elements or layers presented.

The terms “about”, “substantially”, “equal”, or “same” generally meanwithin 20% of a given value or range, or mean within 10%, 5%, 3%, 2%,1%, or 0.5% of a given value or range.

Although terms such as first, second, third, etc., may be used todescribe diverse constituent elements, such constituent elements are notlimited by the terms. The terms are used only to discriminate aconstituent element from other constituent elements in thespecification. The claims may not use the same terms, but instead mayuse the terms first, second, third, etc. with respect to the order inwhich an element is claimed. Accordingly, in the following description,a first constituent element may be a second constituent element in aclaim.

The technical features in different embodiments described in thefollowing can be replaced, recombined, or mixed with one another toconstitute another embodiment without departing from the spirit of thepresent disclosure.

Referring to FIG. 1, it is a schematic diagram illustrating across-sectional view of a lighting device according to a firstembodiment of the present disclosure. The lighting device may include adisplay device, an electronic device, a flexible device, or othersuitable devices, but is not limited thereto. In some embodiments, thelighting device can be applied to a tiled device. For example, thelighting device 10 is a display device, which may include a panel DP anda backlight module BL, and the panel DP is disposed opposite to thebacklight module BL. The panel DP may include a first substrate 100, asecond substrate 102, and a light modulating layer 1042 disposed betweenthe first substrate 100 and the second substrate 102. The firstsubstrate 100 may be disposed between the light modulating layer 1042and the backlight module BL. The first substrate 100 and/or the secondsubstrate 102 may include transparent substrates, for example, a rigidsubstrate includes a glass substrate or a quartz substrate, or aflexible substrate includes a plastic substrate, but not limitedthereto. The material of the plastic substrate may include polyimide(PI), polycarbonate (PC), or polyethylene terephthalate (PET), but notlimited thereto. In one embodiment, the lighting device includes aliquid crystal panel, and the light modulating layer 1042 may be aliquid crystal layer, and some spacers 1041 may be disposed between thefirst substrate 100 and the second substrate 102. Additionally, thepanel DP may also include alignment layers (e.g. PI layers) orelectrodes (e.g. pixel electrodes or common electrodes), a shieldingstructure 106, but not limited thereto. The first substrate 100 may bean array substrate. The second substrate 102 may be a color filtersubstrate or protective substrate, but not limited thereto. For example,transistors, signal lines, scan lines, data lines, or insulating layersmay be disposed on the first substrate 100, but is not limited thereto.For example, the shielding structure 106 may be disposed between thesecond substrate 102 and the first substrate 100. The shieldingstructure 106 may include a plurality of apertures, and each of thelight converting elements (such as the light converting element LCE1,LCE2, or LCE3) may be disposed in the corresponding aperture of theshielding structure 106. The material of the shielding structure 106 mayinclude black photoresist, black printing ink, black resin or othersuitable material or combination thereof, but not limited thereto.

The panel DP may further include a polarizer 1081 and a polarizer 1082.The polarizer 1081 may be disposed between the first substrate 100 andthe backlight module BL, and the polarizer 1082 may be disposed betweenthe light converting elements (such as the light converting elementLCE1, LCE2, or LCE3) and the light modulating layer 1042. However,polarizer 1081 and polarizer 1082 are not limited to be disposed at theabove mentioned locations. It should be noted that, in some embodiments,the lighting device has the light modulating layer 1042 (such as LC),the light modulating layer 1042 may be disposed between two polarizersfor adjusting gray scale, so the light converting elements cannot bedisposed between two polarizers. In some embodiments, the polarizer 1081and/or the polarizer 1082 are disposed between the first substrate 100and the second substrate 102, the polarizer 1081 and/or the polarizer1082 may include metal wires, which can be the so-called wire gridpolarizer (WGP), but is not limited thereto. The material of metal wireincludes metal, metal alloy, other suitable material or combinationthereof, but is not limited thereto. In some embodiments, the firstsubstrate 100 and the second substrate 102 may be disposed between thepolarizer 1081 and the polarizer 1082, the material of polarizer 1081and the polarizer 1082 may include protective film, tri-acetatecellulose (TAC), polyvinyl alcohol (PVA), pressure sensitive adhesive(PSA), release film, but is not limited thereto. In addition, the panelDP may further include at least one optical film 110 disposed betweenthe panel DP and the backlight module BL. In some embodiments, theoptical film 110 includes dual brightness enhancement film (DBEF), prismfilm, other suitable optical films, or combination thereof, but notlimited thereto.

The backlight module BL may include a light source 112 and a light guideplate 114. As shown in FIG. 1, the backlight module BL may be anedge-lit type backlight module, and the light source 112 may be disposednear at least one sidewall of the light guide plate 114, but not limitedthereto. The light source 112 may include light emitting diode (LED),micro-LED, mini-LED, organic light-emitting diode (OLED), fluorescentmaterial, phosphor, other suitable light sources, or combinationthereof, but not limited thereto. In one embodiment, the backlightmodule BL can emit blue light or UV light, but not limited thereto.

As shown in FIG. 1, the lighting device 10 can include a first lightingunit LU1, a second lighting unit LU2, and a third lighting unit LU3. Thefirst lighting unit LU1 includes a first light emitting element LE1 anda first light converting element LCE1, the second lighting unit LU2includes a second light emitting element LE2 and a second lightconverting element LCE2, and the third lighting unit LU3 includes athird light emitting element LE3 and a third light converting elementLCE3. One of the lighting units may correspond to a structure includinga vertical stack of layers (or elements) of a portion of the lightingdevice 10. For example, one of the lighting units may be a portion ofthe lighting device 10 emitting one color (e.g. red, green, or blue, butnot limited thereto). One of the lighting units may correspond to one ofthe apertures of the shielding structure 106. In one of the lightingunits, the light converting element can be disposed on the lightemitting element. For example, the first light converting element LCE1is disposed on the first light emitting element LE1, the second lightconverting element LCE2 is disposed on the second light emitting elementLE2, and the third light converting element LCE3 is disposed on thethird light emitting element LE3. Additionally, the light modulatinglayer 1042 can be disposed between the light emitting elements and thelight converting elements.

A portion of the backlight module BL (such as the light guide plate 114)in FIG. 1 corresponding to the first light converting element LCE1 in anormal direction V may be regarded as the first light emitting elementLE1, a portion of the backlight module BL corresponding to the secondlight converting element LCE2 in the normal direction V may be regardedas the second light emitting element LE2, and a portion of the backlightmodule BL corresponding to the third light converting element LCE3 inthe normal direction V may be regarded as the third light emittingelement LE3. The normal direction V is perpendicular to the firstsubstrate 100.

The first light converting element LCE1, the second light convertingelement LCE2, or the third light converting element LCE3 may includequantum dots, fluorescent materials, phosphorescent materials, colorfilter layer, other suitable materials or the combination thereof, butnot limited thereto. The quantum dots may be made of a semiconductornano-crystal structure, and can include CdSe, CdS, CdTe, ZnSe, ZnTe,ZnS, HgTe, InAs, Cd1-xZnxSe1-ySy, CdSe/ZnS, InP, and GaAs, but notlimited thereto. Quantum dots generally have a particle size between 1nanometer (nm) and 30 nm, 1 nm and 20 nm, or 1 nm and 10 nm. In oneembodiment, quantum dots are excited by an input light emitted by thebacklight module BL, the input light will be converted into an emittedlight with different wavelength by quantum dots. The color of theemitted light may be adjusted by the material or size of the quantumdots. In other embodiments, the quantum dots may include sphereparticles, rod particles or particles with any other suitable shapes aslong as the quantum dots could emit light with suitable color.

As shown in FIG. 1, the first light converting element LCE1 may includequantum dots QD1, the quantum dots QD1 can be excited by a portion ofthe input light IL1, and the portion of the input light IL1 may beconverted into a light CL1 by the quantum dots QD1. Since the conversionefficiency of quantum dots may not be 100%, another portion of the inputlight IL1 may not be converted into the light CL1, and a first light OL1may be the mixture of the light CL1 and the unconverted input light IL1.The first light OL1 may be an output light emitted from the firstlighting unit LU1. In this disclosure, the output light could beregarded as the final visual light of the lighting device 10 perceivedby the observer.

As shown in FIG. 1, the second light converting element LCE2 may includequantum dots QD2, the quantum dots QD2 can be excited by a portion ofthe input light IL2, and the portion of the input light IL2 may beconverted into a light CL2 by the quantum dots QD2. The quantum dots QD2may be different from the quantum dots QD1. A second light OL2 may bethe mixture of the light CL2 and the unconverted input light IL2. Thesecond light OL2 may be an output light emitted from the second lightingunit LU2.

In one embodiment, a third light OL3 emitted by the third lighting unitLU3 can be blue light. Since the third light emitting element LE3 emitsblue light, the third light converting element LCE3 may be replaced by atransparent layer, which has no quantum dots therein. The transparentlayer may include transparent dielectric material, but not limitedthereto. In some embodiments, the third light converting element LCE3may include a blue color filter. In some embodiment, the third lightconverting element LCE3 is not included in the third electronic unitEU3. In some embodiments, the third light converting element LCE3 mayinclude suitable type of quantum dots to adjust the wavelength of thethird light OL3.

In some embodiments, a plurality of light absorbing materials LA may bedisposed in the first light converting element LCE1 and/or the secondlight converting element LCE2. In some embodiments, the light absorbingmaterials LA may be disposed on the first light converting element LCE1and/or the second light converting element LCE2, for example, the lightabsorbing materials LA may be mixed in a suitable layer(s) above thefirst light converting element LCE1 and/or the second light convertingelement LCE2. The light absorbing material LA can be used for absorbinga portion of the unconverted input light IL1 (and/or a portion of theunconverted input light IL2), so the amount of the unconverted inputlight IL1 (and/or input light IL2) can be reduced. The light absorbingmaterials LA may include benzotriazole (C₆H₅N₃), titanium oxide (TiO₂),zirconium oxide (ZrO₂), other suitable materials or the combinationthereof, but not limited thereto. C₆H₅N₃, TiO₂, or ZrO₂ can absorb thelight having the wavelength less than 450 nm or less than 400 nm, butnot limited thereto.

For example, the content ratio of C₆H₅N₃ in the light absorbing materialLA may be in a range from 0.1% to 20.2% (0.1%≤content ratio≤20.2%), andthe content ratio of TiO₂ in the light absorbing material LA may be in arange from 0.2% to 19.6% (0.2%≤content ratio≤19.6%). In this situation,the transmittance of the light absorbing material LA corresponding tothe light having the wavelength of 450 nm may be in a range from 86.5%to 91.2% (86.5%≤transmittance≤91.2%), the transmittance of the lightabsorbing material LA corresponding to the light having the wavelengthof 400 nm may be in a range from 1.66% to 11.8%(1.66%≤transmittance≤11.8%), and the transmittance of the lightabsorbing material LA corresponding to the light having the wavelengthof 380 nm may be in a range from 0.0005% to 0.005%(0.0005%≤transmittance 0.001%≤0.005%). The content ratio of differentmaterials can be adjusted according to the requirement.

In addition, the light absorbing material LA may include yellow pigment(Y-pigment), yellow dye (Y-dye), YAG phosphor, other suitable materialsor the combination thereof, but not limited thereto. Y-pigment mayinclude C₁₆H₁₂Cl₂N₄O₄, Y 184, Y 185, Y 189, Y 194, Y 213, Y 120, Y 128,Y 138, Y 139, Y 150, or Y 151. Y-dye may include C₂₆H₁₈N₄Na₂O₈S₂. YAGphosphor may include YAG:Ce³⁺, Y₃Al₅O₁₂:Ce³⁺, or other commercial YAGphosphors, but not limited thereto.

Referring to FIG. 2, it is a schematic diagram illustrating the lightspectrum of the output light emitted by the first lighting unit or thesecond lighting unit. The light spectrums of the first light OL1 and thesecond light OL2 may have similar features or characteristics. Thefeatures or characteristics of the light spectrum LS described below maybe applied to the first lighting unit LU1 and the second lighting unitLU2.

In FIG. 2, the light spectrum LS may include a main wave MW and asub-wave SW. The main wave MW may represent the light CL1 (or the lightCL2) converted by the first light converting element LCE1 (or the secondlight converting element LCE2). A main peak of the main wave MWcorresponds to a wavelength Wm, and the wavelength Wm may be in a rangefrom 520 nm to 780 nm. “Main peak of the main wave MW” is defined as acrest of the main wave MW1. “Main peak of the main wave” in other lightspectrums may also be defined by the same way described above. Inaddition, a portion of the input light may be converted by the firstlight converting element LCE1 (or the second light converting elementLCE2), the intensity of the main peak of the main wave MW is greaterthan the intensity of the sub peak of the sub-wave SW.

The sub-wave SW may represent the unconverted input light IL1 in thefirst light OL1 (or the unconverted input light IL2 in the second lightOL2). It is noteworthy that the sub-wave SW corresponds to theunconverted input light. A sub peak of the sub-wave SW corresponds to awavelength W1 in the range from 400 nm to 470 nm, thus the sub-wave SWmay correspond to blue light. “Sub peak of the sub-wave SW” is definedas a crest of the sub-wave SW. “Sub peak of sub-wave” in other lightspectrums may also be defined by the same way described above. In someembodiments, the light absorbing material LA may have higher absorbancecorresponding to the light with shorter wavelength (such as less than orequal to 400 nm, but not limited thereto), so the waveform of thesub-wave SW may be asymmetric. As shown in the enlargement (a) of thesub-wave SW in FIG. 2, a first sub peak integral SI1 of the lightspectrum LS is the intensity integral of a portion of the waveform ofthe sub-wave SW. The first sub peak integral SI1 is calculated from thewavelength of the wavelength W1 minus 20 nm (W1 (nm)−20 (nm)) to thewavelength W1. In addition, a second sub peak integral SI2 of the lightspectrum LS is the intensity integral of another portion of the waveformof the sub-wave SW. The second sub peak integral SI2 is calculated fromthe wavelength W1 to the wavelength of the wavelength W1 plus 20 nm (W1(nm)+20 (nm)). Since the waveform of the sub-wave SW may be asymmetric,the second sub peak integral SI2 is different from the first sub peakintegral SI1, and the second sub peak integral SI2 is greater than thefirst sub peak integral SI1. A ratio of the first sub peak integral SI1to the second sub peak integral SI2 (SI1/SI2) can be in a range from 20%to 98% (20%≤SI1/SI2≤98%).

In addition, an intensity integral MI of the main wave MW can becalculated from 521 nm to 780 nm. A ratio of the first sub peak integralSI1 to the intensity integral MI of the main wave MW can be in a rangefrom 0.05% to 2% (0.05%≤SI1/MI≤≤2%), and a ratio of the second intensityintegral SI2 to the intensity integral MI of the main wave MW (SI2/MI)can be in a range from 0.05% to 10% (0.05%≤SI2/MI≤10%).

As shown in the enlargement (b) of the sub-wave SW in FIG. 2, the subpeak of the sub-wave SW corresponds to an intensity I1, a wavelength W2and a wavelength W3 respectively correspond to an intensity I2 of a halfof the intensity I1, and the wavelength W2 is less than the wavelengthW3. An intensity integral of the sub-wave SW of the light spectrum LScalculated from a wavelength W4 to the wavelength W2 is defined as athird sub peak integral SI3, and the wavelength W4 is equal to thewavelength W2 minus 20 nm (W4 (nm)=W2 (nm)−20 (nm)). Another intensityintegral of the sub-wave SW of the light spectrum LS calculated from thewavelength W3 to a wavelength W5 is defined as a fourth sub peakintegral SI4, and the wavelength W5 is equal to the wavelength W3 plus20 nm (W5 (nm)=W3 (nm)+20 (nm)). The third sub peak integral SI3 isdifferent from the fourth sub peak integral SI4, and a ratio of thethird sub peak integral SI3 to the fourth sub peak integral SI4(SI3/SI4) can be in a range from 4% to 30% (4%≤SI3/SI4≤30%).

Referring to FIG. 3, it is a schematic diagram illustrating the lightspectrums of the output lights emitted by the first lighting unit andthe second lighting unit according to the first embodiment. In thespectrum diagram (a) of FIG. 3, the first light OL1 emitted by the firstlighting unit LU1 has a first light spectrum LS1 including a main waveMW1 and a sub-wave SW1, and the second light OL2 emitted by the secondlighting unit LU2 has a second light spectrum LS2 including a main waveMW2 and a sub-wave SW2. The main wave MW1 and the main wave MW2respectively correspond to the light CL1 and the light CL2 in FIG. 1,the main wave MW1 can have a main peak MP1 between 525 nm and 585 nm,and the main wave MW2 can have a main peak MP2 between 595 nm and 775 nmas shown in the spectrum diagram (a) of FIG. 3. The sub-wave SW1 and thesub-wave SW2 respectively correspond to the unconverted input light IL1and the unconverted input light IL2 in FIG. 1. As shown in the spectrumdiagram (a) of FIG. 3, the sub-wave SW1 can have a first sub peak SP1between 400 nm and 470 nm, and the sub wave SW2 can have a second subpeak SP2 between 400 nm and 470 nm. The intensity of the first sub peakSP1 can be different from the intensity of the second sub peak SP2. Forexample, the intensity of the first sub peak SP1 may be greater than theintensity of the second sub peak SP2, but not limited thereto. In someembodiments, the integral area of the first light spectrum LS1 maypartially overlaps the integral area of the second light spectrum LS2.For example, the integral area of the sub wave SW2 of second lightspectrum LS2 may be overlapped with the integral area of the sub waveSW1 of first light spectrum LS1, which means that the integral area ofthe first light spectrum LS1 may partially overlaps the integral area ofthe second light spectrum LS2, but not limited thereto.

As shown in the enlargement (b) of the sub-wave SW1 and the sub-wave SW2in FIG. 3, similar to the description above, the sub-wave SW1 in thefirst light spectrum LS1 can have a first sub peak integral SI11 and asecond sub peak integral SI21, and the sub-wave SW2 in the second lightspectrum LS2 can have a first sub peak integral SI12 and a second subpeak integral SI22. The first sub peak SP1 of the first light spectrumLS1 corresponds to a wavelength W11, the second sub peak SP2 of thesecond light spectrum LS2 corresponds to a wavelength W12, and thewavelength W11 and the wavelength W12 may be the same in FIG. 3, but notlimited thereto. In some embodiments, the wavelength W11 and thewavelength W12 may be different. The first sub peak integral SI11 iscalculated from the wavelength of the wavelength W11 minus 20 nm (W11(nm)−20 (nm)) to the wavelength W11, and the second sub peak integralSI21 is calculated from the wavelength W11 to the wavelength of thewavelength W11 plus 20 nm (W11 (nm)+20 (nm)). For example, the first subpeak integral SI11 may be calculated by SI11=∫_(λ=W11−20)^(λ=W11)I(λ)dλ, the second sub peak integral SI21 may be calculated bySI21=∫_(λ=W11) ^(λ=W11+20)I(λ)dλ, wherein I is the intensity of thesub-wave SW1 and λ is the wavelength. The first sub peak integral SI12is calculated from the wavelength of the wavelength W12 minus 20 nm (W12(nm)−20 (nm)) to the wavelength W12, and the second sub peak integralSI22 is calculated from the wavelength W12 to the wavelength of thewavelength W12 plus 20 nm (W12 (nm)+20 (nm)). For example, the first subpeak integral SI12 may be calculated by SI12=∫_(λ=W12−20)^(λ=W12)I(λ)dλ, the second sub peak integral SI22 may be calculated bySI22=∫_(λ=W12) ^(λ=W12+20)I(λ)dλ, wherein I is the intensity of thesub-wave SW2 and λ is the wavelength. In some embodiments, a ratio ofthe first sub peak integral SI11 to the second sub peak integral SI21(SI11/SI21) of the first light spectrum LS1 is different from a ratio ofthe first sub peak integral SI12 to the second sub peak integral SI22(SI12/SI22) of the second light spectrum LS2.

As shown in the enlargement (c) of the sub-wave SW1 and the sub-wave SW2in FIG. 3, a fifth sub peak integral SI51 of the sub-wave SW1 of thefirst light spectrum LS1 can be calculated from 380 nm to the wavelengthW11 of the first sub peak SP1, and a sixth sub peak integral SI61 of thesub-wave SW1 of the first light spectrum LS1 can be calculated from thewavelength W11 of the first sub peak SP1 to 520 nm. For example, thefifth sub peak integral SI51 may be calculated by SI51=∫_(λ=380 nm)^(λ=W11)I(λ)dλ, the sixth sub peak integral SI61 may be calculated bySI61=∫_(λ=W11) ^(λ=520 nm)I(λ)dλ, wherein I is the intensity of thesub-wave SW1 and λ is the wavelength. In addition, a fifth sub peakintegral SI52 of the sub-wave SW2 of the second light spectrum LS2 canbe calculated from 380 nm to the wavelength W12 of the second sub peakSP2, and a sixth sub peak integral SI62 of the sub-wave SW2 of thesecond light spectrum LS2 can be calculated from the wavelength W12 ofthe second sub peak SP2 to 520 nm. For example, the fifth sub peakintegral SI52 may be calculated by SI52=∫_(λ=380 nm) ^(λ=W12)I(λ)dλ, thesixth sub peak integral SI62 may be calculated by SI62=∫_(λ=W12)^(λ=520 nm)I(λ)dλ, wherein I is the intensity of the sub-wave SW2 and λis the wavelength. In some embodiments, a ratio of the fifth sub peakintegral SI51 to the sixth sub peak integral SI61 (SI51/SI61) isdifferent from a ratio of the fifth sub peak integral SI52 to the sixthsub peak integral SI62 (SI52/SI62).

In some embodiments, the first light OL1 can be green light, the secondlight OL2 can be red light, and the third light OL3 can be blue light,but not limited thereto. In some embodiments, the lighting device 10 mayinclude other lighting units emitting a light with a color differentfrom the first light OL1, the second light OL2 and the third light OL3.In some embodiments, the lighting device 10 may include other lightingunits emitting a light with different wavelength.

Referring to FIG. 4 to FIG. 6, FIG. 4 is a CIE 1931 chromaticitydiagram, FIG. 5 is a schematic diagram illustrating the enlargement ofthe region G in FIG. 4 with points of different output lights of thefirst lighting units, and FIG. 6 is a schematic diagram illustrating theenlargement of the region R in FIG. 4 with points of different outputlights of the second lighting units. Color gamut may be commonlyrepresented by an area in the CIE 1931 chromaticity diagram of FIG. 4.The numbers marked along a curved edge CE may represent the wavelengths.In FIG. 4, the color of lights having x-y coordinates located in aregion Y may be yellow or close to yellow.

In FIG. 5, a region CS can represent the color space of the lightingdevice 10, in which a point G0 may represent the green primary color,and points G1, G2, G3 correspond to the x-y coordinates of the firstlights OL1 emitted by the first lighting units LU1 measured from someembodiments, but not limited thereto. The x-y coordinates of point G0,G1, G2, G3 may be as follows, G0 xy=(0.17, 0.797), G1 xy=(0.26, 0.705),G2 xy=(0.27, 0.699), G3 xy=(0.275, 0.698). Comparing the points G1, G2,G3 with the point G0, it can be confirmed that the color of the firstlight OL1 can be adjusted toward the region Y, and the first light OL1emitted by the first lighting units LU1 can be yellower because thereduction of the intensity of blue light in the first light OL1. In someembodiments, reduction of the intensity of blue light in the first lightOL1 may be caused by the introduction of the light absorbing materialLA. The x-y coordinate of the first light OL1 in some embodiments can belocated in the region G of the chromaticity diagram. For example, agreen x-coordinate value in a CIE 1931 color gamut of the lightingdevice 10 is in a range from 0.17 to 0.29 (0.17≤x≤0.29), and a greeny-coordinate value in the CIE 1931 color gamut of the lighting device 10is in a range from 0.675 to 0.797 (0.675≤y≤0.797).

As shown in FIG. 6, a point R0 may represent the red primary color ofthe color space of the lighting device 10, and points R1, R2, R3, R4correspond to the x-y coordinates of the second lights OL2 emitted bythe second lighting units LU2 measured from some embodiments. The x-ycoordinates of point R0, R1, R2, R3, R4 may be as follows, R0 xy=(0.708,0.292), R1 xy=(0.693, 0.303), R2 xy=(0.6915, 0.3035), R3 xy=(0.687,0.3045), R4 xy=(0.684, 0.3082). Comparing the points R1, R2, R3, R4 withthe point R0, it can be confirmed that the color of the second light OL2can be adjusted toward the region Y, and the second light OL2 emitted bythe second lighting units LU2 can be yellower because the reduction ofthe intensity of blue light in the second light OL2. In someembodiments, reduction of the intensity of blue light in the secondlight OL2 may be caused by the introduction of the light absorbingmaterial LA. The x-y coordinate of the second light OL2 in someembodiments can be located in the region R of the chromaticity diagram.For example, a red x-coordinate value in the CIE 1931 color gamut of thelighting device 10 is in a range from 0.68 to 0.708 (0.68≤x≤0.708), anda red y-coordinate value in the CIE 1931 color gamut of the lightingdevice 10 is in a range from 0.292 to 0.31 (0.292≤y≤0.31).

Since the blue light (i.e. the sub-wave SW in the light spectrum LS) inthe first light OL1 and the second light OL2 may be reduced, or thelight mixed by the first light OL1 and/or the second light OL2 shiftingtoward blue region may be reduced. Therefore, the light having the colorof yellow or close to yellow can be obtained or provided by the lightingdevice 10. In some embodiments, the yellow lighting units may not berequired to be disposed in the lighting device 10. When the color spaceof the lighting device 10 is adjusted (e.g. by reducing the blue light),the visual perception of the observer may be improved.

The spectrums may be measured by the spectroradiometer. Thespectroradiometer may be disposed at a side of the emitting surface ofthe intact lighting device 10 that is far from the backlight module BLor light emitting elements while measuring. The lighting device 10 maybe set up to turn on at least one of the first lighting units LU1 (or atleast one of the second lighting units LU2), and the lighting device 10may emit the first light OL1 (or the second light OL2). The firstlighting unit(s) LU1 or the second lighting unit(s) LU2 may be operatedin the condition of maximum gray level while measuring. Thespectroradiometer may include CA-210, CS 1000T, CS 2000 or othersuitable instrument, but not limited thereto.

The technical features in different embodiments described in thisdisclosure can be replaced, recombined, or mixed. For making it easierto compare the difference between these embodiments, the followingdescription will detail the dissimilarities among different embodimentsand the identical features will not be redundantly described.

Referring to FIG. 7, it is a schematic diagram illustrating across-sectional view of a lighting device according to a secondembodiment. Different from the first embodiment, the light convertingelements (such as LCE1, LCE2, and LCE3) can be disposed in the backlightmodule BL. In some embodiments, the light converting elements (such asLCE1, LCE2, and LCE3) can be disposed between an optical layer 116 andpanel DP. In some embodiments, the light converting elements can bedisposed on an optical layer 116 and separated by an isolation structure118 to form an optical structure, which may be so-called as the“quantum-dot color-filter on light guide” structure. The lightconverting elements can be covered by a planarization layer 120, but notlimited thereto. The optical layer 116 may include the light guideplate, diffuser plate or other optical films (or plates). The materialof the isolation structure 118 and the material of the planarizationlayer 120 may include transparent materials, insulating materials, othersuitable materials or the combination thereof, but not limited thereto.In FIG. 7, the backlight module BL may be a direct-lit type backlightmodule or an edge-lit type backlight module. In one embodiment, thebacklight module BL is a direct-lit type backlight module, and thebacklight module BL may include a plurality of light sources 122disposed under the optical layer 116.

In some embodiments, a plurality of blocking structures BF may berespectively disposed on the first light converting element LCE1 and thesecond light converting element LCE2, and the light absorbing materialsLA can be disposed in the blocking structures BF, as shown in FIG. 7. Insome embodiments, the light absorbing materials LA may be disposed onthe light emitting elements (such as LE1 and LE2) and/or the lightconverting elements (such as LCE1 and LCE2). In some embodiment, theblocking structures BF may be contacted to the top surfaces (or othersurfaces) of the first light converting element LCE1 and/or the secondlight converting element LCE2, but not limited thereto. In someembodiments, the blocking structures BF may include yellow colorfilters, but not limited thereto. It should be noted that the blockingstructures BF may include a main material and at least one of theblocking materials (or the light absorbing material LA) disposed in themain material, but not limited thereto. The main material of theblocking structures BF may include transparent materials, insulatingmaterials, other suitable materials or the combination thereof, but notlimited thereto. The blocking materials may block or filter the bluelight, but not limited thereto. The blocking materials and the lightabsorbing material LA may be similar, and the description will not berepeated. In some embodiments, the blocking structures BF can bedisposed in the apertures AP of the shielding structure 106 in the firstlighting unit LU1 and/or the second lighting unit LU2, but not limitedthereto.

In some embodiments, a portion of the light sources 122 and a portion ofthe optical layer 116 in FIG. 7 corresponding to the first lightconverting element LCE1 in the normal direction V may be regarded as thefirst light emitting element LE1. Additionally, the second lightemitting element LE2 and the third light emitting element LE3 may alsobe defined by the above method. In some embodiments, the third lightconverting element LCE3 can include quantum dots QD3, the quantum dotsQD3 can be excited by a portion of the input light emitting from thethird light emitting element LE3, and the portion of the input light maybe converted into blue light having different wavelength of main peak bythe quantum dots QD3.

Referring to FIG. 8, it is a schematic diagram illustrating across-sectional view of a lighting device according to a thirdembodiment. In some embodiments, the lighting device 10 may includeorganic light emitting diodes (OLED). The light emitting elements (suchas LE1, LE2, and LE3) share a light emitting element LE, but not limitedthereto. The common light emitting element LE may include at least onelight emitting structure. For example, as shown in FIG. 8, the lightemitting element LE includes a plurality of second electrodes EL2, ahole injection layer HIL2, a hole transport layer HTL2, a light emittingstructure LEL2, an electron transport layer ETL2, an electron injectionlayer EIL2, a charge generating layer CGL, a hole injection layer HIL1,a hole transport layer HTL1, a light emitting structure LEL1, anelectron transport layer ETL1, an electron injection layer EIL1, a firstelectrode EL1 sequentially stacked on a TFT substrate in the normaldirection V, but not limited thereto.

The light emitting structure LEL1 and the light emitting structure LEL2may include organic light emitting material or quantum dots, othersuitable materials or the combination thereof, but not limited thereto.The second electrodes EL2 may be one of cathode and anode, and the firstelectrode EL1 may be another one of cathode and anode. The secondelectrodes EL2 are separately disposed in the corresponding the lightingunits. The second electrodes EL2 may be disposed on a passivation layerPL, and a pixel definition layer PDL may be disposed on the secondelectrodes EL2. One of the apertures of the pixel definition layer PDLmay correspond to one of the second electrodes EL2, and the secondelectrodes EL2 may be partially exposed through the apertures of thepixel definition layer PDL. One of the second electrodes EL2 maypenetrate through the passivation layer PL to be electrically connectedto a transistor of the lighting unit. In some embodiments, the lightemitting structure LEL1, LEL2 may correspond to the lighting units LU1,LU2, and LU3, but not limited thereto. In some embodiments, othercomponents may be disposed between the light emitting structures LEL1,LEL2. In some embodiments, the material of the light emitting structuresLEL1, LEL2 may be the same or different. In addition, the first lightconverting element LCE1, the second light converting element LCE2, andthe third light converting element LCE3 may be disposed on a substrateSU, and the substrate SU may be disposed opposite to the array substrate(not shown), but not limited thereto. In some embodiments, the firstlight converting element LCE1, the second light converting element LCE2,and the third light converting element LCE3 may be disposed or formed onthe same substrate with the light emitting element LE and disposed onthe light emitting element LE, and the substrate SU may be a protectivelayer or a protective film, but it is not limited thereto. In someembodiments, the above layers (or elements) may be added or removeddepending on the situation, and are not limited thereto.

In addition, the stack structure of the light emitting element LE may beregarded as an integration of various light emitting components, whereinthe light emitting components may be electrically connected in series.In some embodiments, the light emitting components may be disposed sideby side laterally, the charge generating layer may not be disposed inthe light emitting component, and the emitting components may beelectrically connected in parallel.

In some embodiment, one of the lighting units (such as LU1, LU2, or LU3)may include at least one light source disposed in the light emittingelement (such as LE1, LE2, or LE3). The light sources may include LED,micro-LED, mini LED, quantum dots LEDs (QLEDs or QD-LEDs), but notlimited thereto. In some embodiments, one of the light convertingelements (such as LCE1, LCE2, or LCE3) may be disposed on a top surfaceof the corresponding light sources. In some embodiments, one of thelight converting elements (such as LCE1, LCE2, or LCE3) may disposed on(or cover) the top surface and the sidewalls of the corresponding lightsources.

In summary, according to the light spectrums of the first light and thesecond light emitted by the lighting device, since the blue light (i.e.the sub-waves in the light spectrums) in the first light and the secondlight is reduced, the phenomenon of the light mixed by the first lightand the second light shifting toward blue light region can be reduced.Therefore, the light having the color of yellow or close to yellow canbe obtained or provided by the lighting device when the first light andthe second light are used for mixing colors, and additional yellowlighting units may not be required to be disposed in the lightingdevice. When the color space of the lighting device is adjusted orshrank (e.g. by reducing the blue light for eye-protection concerns),the yellow region of the color space can still be retained, and it isalso beneficial to the visual perception of the user.

Those skilled in the art will readily observe that numerousmodifications and alterations of the device and method may be made whileretaining the teachings of the disclosure. Accordingly, the abovedisclosure should be construed as limited only by the metes and boundsof the appended claims.

What is claimed is:
 1. A lighting device, comprising: a lighting unitemitting a light spectrum having a main peak between 520 nm and 780 nmand a sub peak corresponding to a first wavelength between 400 nm and470 nm, wherein a second sub peak integral of the light spectrum isgreater than a first sub peak integral of the light spectrum, whereinthe first sub peak integral is an integral of the light spectrumcalculated from a wavelength of the first wavelength minus 20 nm to thefirst wavelength, wherein the second sub peak integral is an integral ofthe light spectrum calculated from the first wavelength to a wavelengthof the first wavelength plus 20 nm, wherein a ratio of the first subpeak integral to the second sub peak integral is in a range from 20% to98%.
 2. The lighting device of claim 1, wherein a ratio of the first subpeak integral to an intensity integral of a main wave comprising themain peak is in a range from 0.05% to 2%, and the intensity integral ofthe main wave is calculated from 521 nm to 780 nm.
 3. The lightingdevice of claim 1, wherein a ratio of the second sub peak integral to anintensity integral of a main wave comprising the main peak is in a rangefrom 0.05% to 10%, and the intensity integral of the main wave iscalculated from 521 nm to 780 nm.
 4. The lighting device of claim 1,wherein a red x-coordinate value in a CIE 1931 color gamut of thelighting device is in a range from 0.68 to 0.708.
 5. The lighting deviceof claim 1, wherein a red y-coordinate value in a CIE 1931 color gamutof the lighting device is in a range from 0.292 to 0.31.
 6. The lightingdevice of claim 1, wherein a green x-coordinate value in a CIE 1931color gamut of the lighting device is in a range from 0.17 to 0.29. 7.The lighting device of claim 1, wherein a green y-coordinate value in aCIE 1931 color gamut of the lighting device is in a range from 0.675 to0.797.
 8. The lighting device of claim 1, wherein a ratio of a third subpeak integral of the light spectrum to a fourth sub peak integral of thelight spectrum is in a range from 4% to 30%, wherein the sub peakcorresponds to a first intensity, a second intensity of a half of thefirst intensity in the light spectrum corresponds to a second wavelengthand a third wavelength, and the second wavelength is less than the thirdwavelength, wherein the third sub peak integral is an integral of thelight spectrum calculated from a fourth wavelength to the secondwavelength, and the fourth wavelength is the second wavelength minus 20nm, wherein the fourth sub peak integral is an integral of the lightspectrum calculated from the third wavelength to a fifth wavelength, andthe fifth wavelength is the third wavelength plus 20 nm.
 9. The lightingdevice of claim 1, wherein the lighting unit comprises a light emittingelement and a light converting element disposed on the light emittingelement.
 10. The lighting device of claim 9, wherein the light emittingelement comprises at least one light emitting structure.
 11. Thelighting device of claim 9, further comprising a light modulating layerdisposed between the light emitting element and the light convertingelement.
 12. The lighting device of claim 9, wherein the lighting unitfurther comprises a light absorbing material disposed in the lightconverting element.
 13. The lighting device of claim 9, wherein thelighting unit further comprises a light absorbing material disposed onthe light emitting element or the light converting element.
 14. Thelighting device of claim 9, wherein the lighting unit further comprisesa blocking structure disposed on the light converting element.
 15. Thelighting device of claim 1, wherein the lighting unit further comprisesa light absorbing material, and the light absorbing material has higherabsorbance corresponding to a light with shorter wavelength.
 16. Alighting device, comprising: a first lighting unit emitting a firstlight spectrum having a main peak between 525 nm and 585 nm and a firstsub peak corresponding to a first wavelength between 400 nm and 470 nm;and a second lighting unit emitting a second light spectrum having amain peak between 595 nm and 775 nm and a second sub peak correspondingto a second wavelength between 400 nm and 470 nm, wherein an intensityof the first sub peak is different from an intensity of the second subpeak, wherein an integral area of the first light spectrum partiallyoverlaps an integral area of the second light spectrum.
 17. The lightingdevice of claim 16, wherein a ratio of a first sub peak integral of thefirst light spectrum to a second sub peak integral of the first lightspectrum is different from a ratio of a first sub peak integral of thesecond light spectrum to a second sub peak integral of the second lightspectrum, wherein the first sub peak integral of the first lightspectrum is calculated from a wavelength of the first wavelength minus20 nm to the first wavelength, wherein the second sub peak integral ofthe first light spectrum is calculated from the first wavelength to awavelength of the first wavelength plus 20 nm, wherein the first subpeak integral of the second light spectrum is calculated from awavelength of the second wavelength minus 20 nm to the secondwavelength, wherein the second sub peak integral of the second lightspectrum is calculated from the second wavelength to a wavelength of thesecond wavelength plus 20 nm.
 18. The lighting device of claim 16,wherein the first lighting unit comprises a first light emitting elementand a first light converting element disposed on the first lightemitting element, and the second lighting unit comprises a second lightemitting element and a second light converting element disposed on thesecond light emitting element.
 19. The lighting device of claim 16,wherein a ratio of a fifth sub peak integral of the first light spectrumto a sixth sub peak integral of the first light spectrum is differentfrom a ratio of a fifth sub peak integral of the second light spectrumto a sixth sub peak integral of the second light spectrum, wherein thefifth sub peak integral of the first light spectrum is calculated from380 nm to the first wavelength of the first sub peak, wherein the sixthsub peak integral of the first light spectrum is calculated from thefirst wavelength of the first sub peak to 520 nm, wherein the fifth subpeak integral of the second light spectrum is calculated from 380 nm tothe second wavelength of the second sub peak, wherein the sixth sub peakintegral of the second light spectrum is calculated from the secondwavelength of the second sub peak to 520 nm.